Pneumatic pressure conveying system

ABSTRACT

A conveying conduit is maintained completely filled with dry sand by an air pressurized supply from a refill vessel. The sand is transferred by the conduit to one or more dispensing vessels maintained at a substantially lower pressure than the conveying conduit. The sand is fluidized and selectively discharged from the dispensing vessel under this substantially lower pressure while the sand in the conduit is maintained pressurized when flowing as well as in a static condition when discharge from the dispensing vessel is stopped.

United States Patent Von Funk [54] PNEUMATIC PRESSURE CONVEYING SYSTEM [72] Inventor: Irwin Von Funk, PO. Box 157, Macungie,

[22] Filed: Jan. 12, 1970 21 Appl. No.: 2,064

[52] US. Cl ..302/53 [51] Int. Cl ..B65g 53/40 [58] Field ofSearch ...302/52, 53,55,35, 63,21

[56] Reierences Cited UNITED STATES PATENTS 2,717,810 9/1955 Hines ..302/53 1,605,732 11/1926 l-ioevel ..302/55 1 1 Feb. 22, 1972 2,924,489 2/1960 Beckmann ..302/52 Primary Examiner-Evon C. Blunk Assistant ExaminerH. S. Lane Attorney-Clarence A. OBrien and Harvey B. Jacobson [57] ABSTRACT A conveying conduit is maintained completely filled with dry sand by an air pressurized supply from a refill vessel. The sand is transferred by the conduit to one or more dispensing vessels maintained at a substantially lower pressure than the conveying conduit. The sand is fluidized and selectively discharged from the dispensing vessel under this substantially lower pressure while the sand in the conduit is maintained pressurized when flowing as well as in a static condition when discharge from the dispensing vessel is stopped.

14 Claims, 2 Drawing Figures PATENTED FEB 2 2 I972 T QQ Irwin van Funk IN VIiN'I'OK.

PNEUMATIC PRESSURE CONVEYING SYSTEM This invention relates to the conveyance of sand orother particulate solids over a relatively long distance from a storage location.

The conveyance of sand by pneumatic means is presently utilized for filling locomotive sandboxes. Conveying systems of this type are, however, plagued by certain problems particularly where the sand is to be conveyed over a relatively long distance. In order to convey the sand from the storage zone to the sandboxes, over a horizontal distance, it is necessary to fluidize or aerate the sand with a fluidizing gas such as air under pressure. A dangerously high pressure must, however, be utilized in order to obtain movement of the fluidized sand over a long distance. Also, high pressure operation is necessary in order to obtain a relatively dense condition of the sand at the delivery end or a high sand-to-air ratio. Further, in

addition to the danger involved in high pressure operation, excessive aeration of the sand often occurs referred to as dusting." Still further, high pressure discharge of the sand from the dispensing vessel is difficult to control. There has also been a loss in time in order to start up operation of prior art pneumatic conveying systems after delivery of sand is stopped because of equalization of pressures and reverse flow of sand internally of the system.

The foregoing problems and drawbacksof prior pneumatic conveying systems for particulate materials has been overcome by the pneumatic conveying system of the present invention. This has been done by utilizing a low pressure discharge of fluidized sand from a dispensing vessel of increased capacity as compared to prior art systems. Also, the conveying system of the present invention provides for continuous refill and high pressure transfer of sand despite the low pressure discharge without any reversal in flow upon closing of the discharge nozzle. When operation of the system is stopped, pressures in the vessels are not equalized and the sand in transit from the storage zone to the dispensing zone is maintained in a pressurized and flowable state. The system is thus maintained in a standby condition for immediate operation upon reopening of the discharge nozzle.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a somewhat schematic, side elevational view with parts shown in section of the pneumatic conveying system of the present invention.

FIG. 2 is an electrical circuit diagram of a timing control device associated with the system illustrated in FIG. 1.

Referring now to the drawings in detail, FIG. 1 illustrates the pneumatic conveying system of the present invention which is generally denoted by reference numeral 10. The basic system illustrated includes an initial transfer vessel 12 to which sand or some other particulate material is delivered from a primary storage by means of gravity flow through conduit 14 upon opening of inlet valve 16. The sand is conducted by means of a transfer conduit assembly 18 from the vessel 12 to a plurality of dispensing vessels 20. While the initial transfer vessel 12 may be located adjacent to the primary storage, each of the dispensing vessels 20 may be supported at substantially the same elevation as vessel 12 and remote therefrom adjacent to a useful location such as a locomotive sandbox. A discharge tube 22 is accordingly connected to the dispensing vessel 20 for selectively controlled discharge of sand from a discharge nozzle 24 upon opening of a discharge control valve 26. Once the system is in operation, the control valve 26 may be opened and closed to control the discharge of sand from the nozzle 24 without any loss in time as hereinbefore indicated since the system will remain in a standbyoperating condition when the control valve 26 is closed.

The sand is delivered from the lower end of the initial transfer vessel 12 by means of the transfer conduit system 18 which includes an outlet elbow 28 connected to the lower end of the vessel 12. The elbow 28 is connected by a pipe section to a connector fitting 30 having a cleanout plug 32. The sand is conducted from the fitting 30 upwardly at approximately degrees by an abruptly rising pipe section 34 which extends from the fitting 30 to another pipe coupling fitting 36 having a cleanout plug 38 at its upper end. After the sand is elevated through the pipe section 34, it is conducted a substantial horizontal distance by a plurality of high pressure pipe sections 40 of constant flow area as shown which are interconnected with each other by full'flow couplings 42. The pipe sections 40 have a slight rise of 2 degrees for example in the direction offlow and have no internal obstructions therein.

Adjacent to each of the dispensing vessels 20 which are spaced apart a substantial distance such as to 75 feet. a sand diverting section 44 is connected to the conduit system to divert flow of sand to a fill pipe section 46 which projects a substantial distance into the upper end of the dispensing vessel 20. The fill pipe section 46 includes a series of .flow portions progressively reduced in flow area relative to the conduit system 18 so as to stop inflow of sand to the vessel 20 when the vessel is completely filled. The conduit system 18 is then sealed by the sand from the interior of the dispensing vessel 20 in order to permit the vessel 20 to be maintained at a substantially lower pressure than the pressure of the sand within the conduit system 18. For this reason, whenever all of the discharge valves 26 are closed so that there is no flow of sand through the conduit system 18, it will remain in a standby condition for immediate delivery of sand upon opening of any of the discharge control valves 26. The sand will of course flow under the inducement of the substantially higher pressure applied thereto at the initial transfer vessel 12 as compared to the lower pressure of the zone in the dispensing vessel 20 to which the sand is delivered in response to depletion of sand therefrom.

The sand within the dispensing vessel 20 is fluidized and maintained pressurized for dispensing purposes at a relatively low pressure by means of a pressure regulating system 48 through which a fluidizing gas such as air is supplied from a suitable source of air under pressure to the dispensing vessel 20. The pressurized air supply conduit 50 is connected by a pressure regulator valve assembly 52 in the pressure regulating system 48 to the inlet side of a check valve 54 and to a secondary pressure regulator valve assembly 56. The pressurized air is reduced in pressure by the secondary regulator 56 for controlling the venting or exhaust of excessive air from the dispensing vessel 20 through a blowoff control valve 58. The pressure regulating valve assemblies 52 and 56, the check valve 54 and the blowoff valve device 58 are well known and 7 per se form no part of the present invention.

The pressurized air at a regulated low pressure is conducted through the check valve 54 and flow control valves 60 and 62 to a primary air injecting nozzle 64 and a secondary air injecting nozzle 66. The air injection nozzles project into air pressure chambers 68 and 70 separated from the sand receiving chamber 72 by a porous type of primary aeration bed 74 and a secondary aeration bed 76. The lower inlet end of an outlet tube 78 is positioned closely above the primary aeration bed 74 and extends upwardly and out of the vessel 20 for connection by the fitting 80 to the discharge tube 22. It will therefore be apparent, that the sand within the chamber 72 will be maintained in a fluidized state adjacent the inlet end of tube 78 and under a relatively low pressure, for easily controlled discharge of sand from the nozzle 24 upon opening of the control valve 26 in order to deliver sand at a relatively dense or high sandto-air ratio without excessive aeration or dusting." Further, the dispensing vessel 20 from which the sand is dispensed, through the nozzle 24, will be maintained filled at all times by transfer of sand thereto from the conduit system 18 with respect to which the dispensing vessel is sealed when filled with sand by the fill pipe section 46 as aforementioned, sand being delivered to the dispensing vessel 20 from the conduit system 18 only in response to depletion of its supply of sand.

The sand within the conduit system 18 is maintained in a pressurized and flowable state at all times because the sand is transferred thereto from a lower chamber 82 within the initial transfer vessel 12 which is continuously pressurized at a relatively high pressure as compared to the relatively low pressure maintained within the dispensing vessel 20. In one embodiment of the invention as shown, air under pressure is supplied through the inlet valve 84 and a high pressure regulator valve 86 to the lower chamber 82 while exerting an upward closing bias on a chamber sealing valve 88 adapted to be seated on the sealing edge of an opening 90 through which communication may be established between the lower chamber 82 and an upper chamber 92 that is alternatively pressurized and vented. Thus, when the upper chamber 92 is pressurized and the sand within the lower chamber 82 becomes depleted, the differential pressure on the chamber sealing valve 88 is such as to open the valve so as to admit additional sand through the opening 90 into the lower chamber 82 in order to refill the same. Since the valve 88 opens only while the upper chamber 92 is pressurized, the lower chamber 82 remains pressurized during the refilling operation. Hence, the sand in transit within the conduit system 18 will also be maintained continuously pressurized. Further, the sand within the conduit system 18 will be maintained in a flowable state by supply of fluidizing air thereto through valve 94 and check valve 96 connected to the outlet elbow 28.

The upper chamber 92 is pressurized upon opening of an air operated valve mechanism 98 to admit air under the regulated pressure through check valves 100 and 102 to the upper chamber 92 while exerting an upward bias on a fill valve 104 adapted to be seated on the sealing edge of an opening 106 through which the upper chamber 92 communicates with the sand receiving zone 108 into which sand is deposited from the primary sand storage by conduit 14. The valve 104 is opened to admit sand into the upper chamber 92 when the chamber is vented by closing of the air operated inlet valve 98 and opening of an air operated exhaust valve 110. Thus, the upper chamber 92 is alternately pressurized and vented so as to be refilled with sand. Toward this end, control over the inlet valve 98 and exhaust valve 110 is exercised by supply of valve operating air pressure through a four-way control valve 112. In one position of the control valve 112 as shown in FIG. 1, pressurized air from the supply conduit 114 is fed to the valve operating conduit 116 so as to open the inlet valve 98 while the valve operating conduit 118 associated with the exhaust valve 110 is connected to the vent line 120 so that the exhaust valve 110 will remain closed. When the control valve 112 is shifted to its other operative position, the connections to the valve operating lines 116 and 118 are reversed so that the inlet valve 98 is closed and the exhaust valve 110 is opened thereby venting the upper chamber 92. The control valve may be periodically shifted between its two operative positions by means of a solenoid actuator 122 in order to meet any desired demand.

FIG. 2 illustrates by way of example one type of control system 124 by means of which the control valve actuator 122 is alternately energized and deenergized for controlling the refill of sand within the initial transfer vessel 12 in accordance with some predetermined demand. The control system 124 is connected to a source of electrical voltage by the powerlines 126 and 128 through which a timing circuit is energized to control energization of the valve actuator 122. Upon closing of the switch 130, a circuit is completed across the powerlines through the forward timer motor 132 in series with timer switch 134 so as to initiate a timing cycle. Once the timing dicated, the lower chamber 82 will be maintained sealed by the sealing valve 88. On the other hand, while the valve actuator 122 was deenergized the upper chamber 92 is pressurized so that transfer of sand from the upper chamber to the lower chamber may occur should the supply of sand within the lower chamber 82 become depleted. After the solenoid actuator 122 is energized during the second mentioned phase of the timing cycle, it is dcenergized again during displacement of the timing switch 132 to its other operative position completing a cir cuit through the reverse timing motor 140. In this fashion, the vessel 12 may be refilled in accordance with the requirements of the system maintaining pressurized sand within the conduit system 18 at all times in a flowable condition.

In view of the low pressure discharge from each of a plurality of nozzles 24 associated with the conveying system, flow of sand may be stopped by a relatively small resistance to flow experienced at the nozzle when the sand receiving container into which the nozzle is inserted is filled. This flow blocking action is similar to that described in connection with the filling of the dispensing vessel 20 through the fill pipe section 46. Thus, each discharge nozzle 24 may be inserted into a sandbox receiver and the valve 26 opened to fill the sandbox without supervision since flow will automatically stop when the sandbox is filled. The nozzle may then be withdrawn after closing the valve 26. Because of this automatic shutoff feature, a considerable savings in time will be realized when servicing a plurality of sandboxes which may be attended to by a single person sequentially inserting and withdrawing the nozzles, without waiting at each sandbox for completion of the sanding operation.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed is:

1. In a system for distributing particulate material, a source of gas under pressure, at least two vessels storing said particu late material, pressure regulating means operatively connecting said source to the vessels for pressurizing the material therein respectively under substantially different pressures. means connecting the source of gas to one of the vessels for fluidizing the material therein, selectively controlled means for dispensing the fluidized material from said one of the vessels to cause depletion of the material therein, transfer conduit means interconnecting said vessels for conducting the pressurized material to said one of the vessels in response to said depletion of the material therefrom, and means for continuously maintaining the conduit means completely filled with the material from the other of the vessels under the pressure therein without affecting the substantially lower pressure maintained in said one of the vessels by the pressure regulating means.

2. The system of claim 1 wherein said means for maintaining the conduit means completely filled comprises a fill pipe section connected to the conduit means and projecting a substantial distance into said one of the vessels, said fill pipe section having a reducing flow area relative to the transfer conduit means causing pressure sealing of the conduit means by the material upon filling of said one of the vessels.

3. The system of claim 2 wherein the other of the vessels further includes a second chamber alternately pressurized and vented, transfer valve means responsive to a predetermined difference in pressure between the second chamber and the continuously pressurized chamber for establishing flow of the material between said chambers, and refill valve means responsive to venting of the second chamber and depletion of the material therein for admitting the material from an external supply.

4. In a system for conveying particulate material between remotely spaced locations, a source of fluidizing gas under pressure, at least two vessels adapted to receive said particulate material, pressure regulating means operatively connecting said source to the vessels for pressurizing the material therein under respectively different pressures, selectively controlled means for discharging fluidized material from one of the vessels to cause depletion of the material therein, transfer conduit means interconnecting said vessels or conducting the pressurized material to said one of the vessels in response to said depletion of the material therefrom, and means maintaining the conduit means completely filled with the pressurized material from the other of the vessels without affecting the substantially lower pressure maintained in said one of the vessels by the pressure regulating means, said selectively controlled means including an outlet tube extending into said one of the vessels, a dispensing nozzle connected to the outlet tube and control valve means connected to the outlet tube for conducting or blocking flow of the fluidized material to the nozzle.

5. The system of claim 1 wherein said other of the vessels includes a continuously pressurized chamber from which the conduit means is supplied with the material.

6. The system of claim 5 wherein said one of the vessels internally mounts a porous fluidizing bed closely spaced from the outlet tube to partition the vessel into a gas chamber and a material receiving chamber.

7. The system of claim 6 wherein said means for maintaining the conduit means completely filled comprises a fill pipe section connected to the conduit means and projecting a substantial distance into the material receiving chamber of said one of the vessels, said fill pipe section having a reducing flow area causing pressure sealing of the conduit means by the material upon filling of the material receiving chamber of said one of the vessels.

8. The system of claim 7 wherein the other of the vessels further includes a second chamber alternately pressurized and vented, transfer valve means responsive to a predetermined difference in pressure between the second chamber and the continuously pressurized chamber for establishing flow of the material between said chambers, and refill valve means responsive to venting of the second chamber and depletion of the material therein for admitting the material from an external supply.

9. The system of claim 5 wherein the other of the vessels further includes a second chamber alternately pressurized and vented, transfer valve means responsive to a predetermined difference in pressure between the second chamber and the continuously pressurized chamber for establishing flow of the material between said chambers, and refill valve means responsive to venting of the second chamber and depletion of the material therein for admitting the material from an external supply.

10. The system of claim 4 wherein said one of the vessels internally mounts a porous fluidizing bed closely spaced from the outlet tube to partition the vessel into a gas chamber and a material receiving chamber.

11. A method of transferring particulate material from a storage zone to a dispensing zone comprising the steps of: selectively discharging the material to atmosphere from the dispensing zone under a relatively low pressure; fluidizing the material within said dispensing zone; conveying the material from the storage zone to the dispensing zone in response to depletion of material from the dispensing zone; continuously pressurizing the storage zone at a relatively high pressure to induce flow of the material; and pressure sealing the material in transit between said zones to maintain the same in a flowable, pressurized state.

12. The method of claim 11 including the step of: limiting the pressure developed within the dispensing zone to maintain said low pressure while there is no discharge of material from the dispensing zone.

13. The method of claim 12 wherein the material is pressure sealed by utilizing the material itself to block flow into the dis ensing zone.

4. The method of claim 11 wherein the material is pressure sealed by utilizing the material itself to block flow into the dispensing zone. 

1. In a system for distributing particulate material, a source of gas under pressure, at least two vessels storing said particulate material, pressure regulating means operatively connecting said source to the vessels for pressurizing the material therein respectively under substantially different pressures, means connecting the source of gas to one of the vessels for fluidizing the material therein, selectively controlled means for dispensing the fluidized material from said one of the vessels to cause depletion of the material therein, transfer conduit means interconnecting said vessels for conducting the pressurized material to said one of the vessels in response to said depletion of the material therefrom, and means for continuously maintaining the conduit means completely filled with the material from the other of the vessels under the pressure therein without affecting the substantially lower pressure maintained in said one of the vessels by the pressure regulating means.
 2. The system of claim 1 wherein said means for maintaining the conduit means completely filled comprises a fill pipe section connected to the conduit means and projecting a substantial distance into said one of the vessels, said fill pipe section having a reducing flow area relative to the transfer conduit means causing pressure sealing of the conduit means by the material upon filling of said one of the vessels.
 3. The system of claim 2 wherein the other of the vessels further includes a second chamber alternately pressurized and vented, transfer valve means responsive to a predetermined difference in pressure between the second chamber and the continuously pressurized chamber for establishing flow of the material between said chambers, and refill valve means responsive to venting of the second chamber and depletion of the material therein for admitting the material from an external supply.
 4. In a system for conveying particulate material between remotely spaced locations, a source of fluidizing gas under pressure, at least two vessels adapted to receive said particulate material, pressure regulating means operatively connecting said source to the vessels for pressurizing the material therein under respectively different pressures, selectively controlled means for discharging fluidized material from one of the vessels to cause depletion of the material therein, transfer conduit means interconnecting said vessels or conducting the pressurized material to said one of the vessels in response to said depletion of the material therefrom, and means maintaining the conduit means completely filled with the pressurized material from the other of the vessels without affecting the substantially lower pressure maintained in said one of the vessels by the pressure regulating means, said selectively controlled means including an outlet tube extending into said one of the vessels, a dispensing nozzle connected to the outlet tube and control valve means connected to the outlet tube for conducting or blocking flow of the fluidized material to the nozzle.
 5. The system of claim 1 wherein said other of the vessels includes a continuously pressurized chamber from which the conduit means is supplied with the material.
 6. The system of claim 5 wherein said one of the vessels internally mounts a porous fluidizing bed closely spaced from the outlet tube to partition the vessel into a gas chamber and a material receiving chamber.
 7. The system of claim 6 wherein said means for maintaining the conduit means completely filled comprises a fill pipe section connected to the conduit means and projecting a substantial distance into the material receiving chamber of said one of the vessels, said fill pipe section having a reducing flow area causing pressure sealing of the conduit means by the material upoN filling of the material receiving chamber of said one of the vessels.
 8. The system of claim 7 wherein the other of the vessels further includes a second chamber alternately pressurized and vented, transfer valve means responsive to a predetermined difference in pressure between the second chamber and the continuously pressurized chamber for establishing flow of the material between said chambers, and refill valve means responsive to venting of the second chamber and depletion of the material therein for admitting the material from an external supply.
 9. The system of claim 5 wherein the other of the vessels further includes a second chamber alternately pressurized and vented, transfer valve means responsive to a predetermined difference in pressure between the second chamber and the continuously pressurized chamber for establishing flow of the material between said chambers, and refill valve means responsive to venting of the second chamber and depletion of the material therein for admitting the material from an external supply.
 10. The system of claim 4 wherein said one of the vessels internally mounts a porous fluidizing bed closely spaced from the outlet tube to partition the vessel into a gas chamber and a material receiving chamber.
 11. A method of transferring particulate material from a storage zone to a dispensing zone comprising the steps of: selectively discharging the material to atmosphere from the dispensing zone under a relatively low pressure; fluidizing the material within said dispensing zone; conveying the material from the storage zone to the dispensing zone in response to depletion of material from the dispensing zone; continuously pressurizing the storage zone at a relatively high pressure to induce flow of the material; and pressure sealing the material in transit between said zones to maintain the same in a flowable, pressurized state.
 12. The method of claim 11 including the step of: limiting the pressure developed within the dispensing zone to maintain said low pressure while there is no discharge of material from the dispensing zone.
 13. The method of claim 12 wherein the material is pressure sealed by utilizing the material itself to block flow into the dispensing zone.
 14. The method of claim 11 wherein the material is pressure sealed by utilizing the material itself to block flow into the dispensing zone. 